Conviction rates for rape and domestic violence cases have risen to an all time high, the director of public prosecutions (DPP) has revealed, amid criticism that too few cases are being brought to court.

Figures released by the Crown Prosecution Service show that the conviction rate for rape prosecutions has increased to the highest on record, from 58% in 2007/8 to 63% in 2012/13. The CPS figures on rape are expressed as a percentage of cases where charges were brought and "flagged" as involving rape. In raw figures, there were 3,692 prosecutions for rape last year, resulting in 2,333 convictions.

The conviction rate for domestic violence has also increased by 1% in the past year to 74%. In 2005/6 it stood at 60%. There were 70,702 cases last year, resulting in 52,549 convictions and 18,153 acquittals.

But Keir Starmer QC has had to defend the CPS's record in response to criticism from the shadow attorney general, Emily Thornberry, that too many perpetrators were walking free.

CPS figures have shown that prosecutions in England and Wales for violence against women and girls have risen from around 75,000 cases in 2007/8 to 91,000 in 2011/2.

Thornberry, the Labour MP for Islington South and Finsbury, asked questions in parliament about how many rape and domestic violence cases referred to the CPS did not result in prosecutions.

The figures she obtained show that, for domestic violence, the proportion of cases where the CPS took no further action remain remarkably consistent despite an overall rise in numbers.

In 2008, 79,195 domestic violence cases were passed to the CPS but 20,467 (25.8%) resulted in no further action being taken. Four years later, in 2012, police passed on 88,202 cases, of which 22,746 end up with the CPS recommending no charges - again 25.8%.

"I am disappointed that the proportion of domestic violence cases where no action at all is taken remains stubbornly high," Thornberry said. "Given that the CPS has rightly made violence against women and girls a priority, I would have expected this proportion to fall."

She added: Thornberry said: "Some progress has been made with rape prosecutions but the fact that one in two cases are not taken up at all still seems very high.

"The CPS recently carried out a very important study of false allegations of rape and domestic violence and found they were extremely rare. This points to the sad conclusion that the vast majority of the rape and domestic violence cases that the CPS is not acting on are genuine and the perpetrators are walking free."Domestic violence cases result in more retractions more than any other offence, he explained. "[A] relatively high number of victims ... will not want to pursue the case or will retract given it's in the context of a relationship and there are children involved.

"What we have done to try and deal with that is build cases on the assumption that the victim may not support it in the end. We encourage the police [to get] the early evidence that would allow us to do that. One of the critical things is a copy of the 999 tape and [record] better videos of the scene....

"Where we get that combination we can pursue a case even if the victim says she doesn't want to support it. And that helps drive up the figures."

On rape, Starmer said the statistics partially reflect the fact that once a case was 'flagged' as rape, it would not necessarily be recorded as a success if it ended up being charged as a different offence.

"We are doing all we can to prosecute rape cases but there are a number of challenges," he said. "Rape often takes place in a private setting where the victim is the only witness but it does mean that victims will almost always have to go to court. We can offer special measures but some victims decide they are not prepared to go to court and face down the person they say is the assailant.

"Many perpertrators target vulnerable victims and that may mean these are people who find it especially difficult to deal withe the criminal justice system."

Starmer said that a correlation could not be drawn between few rape allegations bering false yet almost half of police cases not resulting in charges. "A case may fall for a whole host of evidential reasons," Starmer explained. "A lot of victims don't want to pursue cases and there may be issues of identity. But I can see why that's a legitimate question to ask."

Thornberry also suggested funding cuts may be undermining progress. Starmer admitted he was having to make extensive savings - of 27.5%. "Notwithstanding the significant saving we are making," Starmer said, "we are improving."